Dynamic Modelling and Experimental Testing of a Dynamic Directional Amplification Mechanism for Vibration Mitigation

Abstract

Purpose: Inertial amplification of an oscillating mass has been considered by various researchers as a means to introduce enhanced vibration control properties to a dynamic system. In this paper an experimental prototype of a novel inertial amplifier, namely the Dynamic Directional Amplification mechanism (DDA), is developed and its dynamic response is subsequently evaluated. The DDA is realized by imposing kinematic constraints to the degrees of freedom (DoFs) of a simple oscillator, hence inertia is increased by coupling the horizontal and vertical motion of the model. Methods: The concept and mathematical framework of the amplifier are introduced and then validated with experimental measurements conducted on the vertical shaking table, located in the Dynamics & Acoustics Laboratory, National Technical University of Athens. Results: Analysis indicates the beneficial effect of the DDA to the dynamic response of the oscillator when compared to the initial structure, showcasing a decrease in the acceleration values and shift of the resonating frequency in the derived transfer functions. Conclusions: The key novelty of the DDA lies in its inertial amplification properties, introduced by a simple geometry and easy-to-apply structure. The proposed framework may be incorporated in applications such as sound and vibration isolators, acoustic panels, acoustic and seismic metamaterials and other vibration control devices that aim to explore the DDA’s dynamic amplification properties. The mechanism has been previously applied by the authors to phononic and locally resonant metamaterials aiming to introduce bandgaps within the low-frequency domain. Graphical Abstract: (Figure presented.).